1-[difluoro(trifluoromethoxy)methoxy]-1,2,2-trifluoroethylene

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

December 2019 to March 2020

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

Not GLP

Qualifier:

according to guideline

Guideline:

EU Method A.8 (Partition Coefficient - Shake Flask Method)

Version / remarks:

1995

Deviations:

yes

Remarks:

pH of the aqueous phase before and after the experiment was not reported

Qualifier:

according to guideline

Guideline:

OECD Guideline 107 (Partition Coefficient (n-octanol / water), Shake Flask Method)

Version / remarks:

2008

Deviations:

yes

Remarks:

pH of the aqueous phase before and after the experiment was not reported

GLP compliance:

no

Type of method:

flask method

Partition coefficient type:

octanol-water

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch number of test material:
Solvay Manufacture Plant / Batch number: 190530v10
- Expiration date of the lot/batch:
May 2023
- Purity test date: 12 December 2019

Analytical method:

gas chromatography

Key result

Type:

log Pow

Partition coefficient:

> 2.58

Temp.:

20 °C

Remarks on result:

other: pH not measured

Details on results:

MOVE3 peak was not visible in the aqueous phase.
The concentration of MOVE3 in water was then considered to be lower than the ratio of the limit of quantification divided by the water amount quantified by gas chromatography.
For octanol phase analyses, the massic percentage of MOVE3 was determined by the massic ratio of Move3 divided by octanol.
The n-octanol/water partition coefficient is calculated with the values obtained for the six assays.

Note 1: The OECD guideline 107 specifies that the maximum test item concentration is 0.01 mole per liter in each phase. This corresponds to 2.32 g/L for the MOVE3. This recommendation is met for all tests.

Note 2: MOVE3 is exhibit a particular behavior, it presents a miscibility gap either with water and Octanol: The mixtures MOVE3/Water and MOVE3/Octanol are two liquid phase system when large amount of MOVE3 is added.

Sample	Volumic ratio (Voctanol / Vwater)	Concentration in water phase (g/L)	Concentration in octanol phase (g/L) +- standard deviation	Pow	Log Pow
Assay 1	1/1	< 0.0049	1.91 +- 0.05	> 391.18	> 2.59
Assay 2	1/1	< 0.0051	1.77 +- 0.06	> 344.72	> 2.54
Assay 3	2/1	< 0.0052	2.25 +- 0.01	> 443.90	> 2.65
Assay 4	2/1	< 0.0050	1.79 +- 0.07	> 355.51	> 2.55
Assay 5	1/2	< 0.0052	1.82 +- 0.04	> 350.08	> 2.54
Assay 6	1/2	< 0.0053	2.22 +- 0.10	> 420.63	> 2.62

Conclusions:

The log Kow of MOVE3 was determined to be > 2.58

Executive summary:

The determination of the octanol/water partition coefficient was performed according to the regulation (CE) n°440/2008, A.8: “Partition coefficient”, May 2008 and to the OECD Guideline n° 107: “Partition coefficient (n-octanol/water): Shake Flask Method”, adopted July, 27, 1995 using the shake flask method.

Considering the high volatility of the test item, adaptations to the standard procedure were put in place in order to reduce as much as possible losses of the test item from water to the vapour phase during the measurements:

• Special sealed cells of 1L volume are used for these tests,


• The cells are filled with a mixture of water and octanol corresponding to the needed volumic ratio and thermostated at 20 °C. MOVE3 is then loaded in the cell in liquid form with a syringe.

The use of the cells allows to reduce the shaking and the shear rate in the cells, then the potential emulsion between the two liquid phases. Samples of the octanol phase are taken through the septum of the top of the cell. The samples of the aqueous phase are taken laterally through the lower lateral septum, so that the sampling needle does not pass through the organic phase. This avoids pollution of the samples. 

The assays with volumic ratio octanol/water of 1:1, 1:2 and 2:1 were done twice. For each assay, water and n-octanol phases were sampled after 4 hours of stirring and 15 hours of settling and analyzed with a gas chromatography method.

MOVE3 peak was not visible in the aqueous phase. The concentration of MOVE3 in water was then considered to be lower than the ratio of the limit of quantification divided by the water amount quantified by gas chromatography. For octanol phase analyses, the massic percentage of MOVE3 was determined by the massic ratio of Move3 divided by octanol.

The n-octanol/water partition coefficient was calculated with the values obtained for six assays. The log Kow of MOVE3 was determined to be > 2.58.

Description of key information

The log Kow of MOVE3 is > 2.58.

Additional information

Two studies are available.

In the first one (2017) the shake flask method (described in the OECD guideline No. 107) was technically unfeasible due to the technical impossibility of developing an analytical method for the quantification in octanol. Indeed during the development of the analytical method it was observed that preparing stock and calibration solutions in octanol sufficiently accurate for quantitative analysis of MOVE3 in n-octanol was not possible. Two predictions basing on two different QSAR methods were also tried as part of the experimental study of Kow. The reliability of such predictions was not evaluated, indeed the two values were not consistent and the validity of such calculations is questionable. The HPLC method (described in the OECD guideline No. 117) was tested but proved not applicable since MOVE3 is not detected using UV detection at 210 nm, Refractive Index detection, Evaporative Light Scattering detection or Mass Spectrometric detection. The study is consireded unreliable (Klimisch 3).

The measurement was repeated in 2020 according to the EU method A.8: “Partition coefficient” and to the OECD Guideline n° 107: “Partition coefficient (n-octanol/water): Shake Flask Method”. Considering the high volatility of the test item, adaptations to the standard procedure were put in place in order to reduce as much as possible losses of the test item from water to the vapour phase during the measurements. MOVE3 peak was not visible in the aqueous phase (concentration < LOQ), while it was quantified in the octanol phase, an exact value of Kow was therefore not obtained. The log Kow of MOVE3 was found to be > 2.58.